Effects of Heat Dissipation from Friction Stir Welding to Microstructures of Semi-Solid Cast 6063 Al Alloy

2021 ◽  
Vol 904 ◽  
pp. 70-75
Author(s):  
Chaiyoot Meengam ◽  
Kittima Sillapasa ◽  
Yotsakorn Pratumwal ◽  
Somboon Otarawanna
Keyword(s):  
Friction Stir Welding ◽  
Heat Dissipation ◽  
Maximum Temperature ◽  
Al Alloy ◽  
Element Analysis ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Measurement Results ◽  
6063 Al Alloy ◽  
Semi Solid

In this work, temperature distribution in semi-solid cast 6063 aluminum alloy workpieces during friction stir welding (FSW) was determined by finite element analysis (FEA). The FEA results were validated by comparing them with the measurement results from thermocouples. The maximum temperature of 534.2oC was predicted at the workpiece surface contacted with the tool shoulder. The temperature profiles obtained from FEA were used to explain microstructural changes during FSW. It was observed that relatively high temperature made α-Al grains became elongated and Mg2Si intermatalics turned into a rod-like morphology with round edges.

A Mathematical Formulation for Calculating Temperature Dependent Friction Coefficient Values: Application in Friction Stir Welding (FSW)

2017 ◽  
Vol 379 ◽  
pp. 73-82 ◽  
Author(s):  
Bahman Meyghani ◽  
Mokhtar Awang ◽  
Sattar Emamian
Keyword(s):  
Friction Stir Welding ◽  
Friction Coefficient ◽  
Mathematical Formulation ◽  
Governing Equations ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Precise Calculation ◽  
The Finite Element Analysis

High rotational motion from the welding tool generates a significant amount of the heat during friction stir welding (FSW). Basically, during FSW the heat is mostly coming from the frictional force between the tool shoulder and the plates. Therefore, a precise calculation of the friction coefficient can increase the accuracy of the finite element analysis (FEA) of the process. However, researchers have applied constant values, and that causes a gap between the reality and the simulated model especially after the welding plunging step. In this study, a mathematical formulation is proposed in order to calculate the temperature dependent values of the friction coefficient and also to explore the influence of the temperature in the friction coefficient. To solve the governing equations of the process, the MATLAB®software is used. The results indicate that, from 25°C to the AA 6061-T6 melting point (580°C), the values of the friction coefficient fall steadily in a range of 0.207089 to 0.000582. Furthermore, the material shear stress and the material yield stress decrease consistently as the temperature rises. Consequently, the influence of the temperature in the contact input parameters and the material properties are discussed in detail and a good correlation with the published results is achieved.

Thermo-Mechanical Coupled Analysis of Deformation Behavior in Friction Stir Welding Process of Aluminum 7075 Plate with Conical Pin

2011 ◽  
Vol 338 ◽  
pp. 618-621
Author(s):  
Zheng Hua Guo ◽  
Gang Yao Zhao ◽  
Li Ming Ke ◽  
Li Xing ◽  
Hai Li Li
Keyword(s):  
Friction Stir Welding ◽  
Deformation Behavior ◽  
Maximum Temperature ◽  
Coupled Analysis ◽  
Outer Side ◽  
Fe Model ◽  
Alloy Plate ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Aluminum 7075

A 3D elastic-plastic and coupled thermo-mechanical FE model for friction stir welding(FSW) of aluminum 7075 plate with conical pin was developed based on the dynamic explicit code ABAQUS/explicit. Then temperature distribution and deformation behavior of 7075 aluminum alloy plate in FSW process were simulated and analyzed. The results show that the temperature is distributed in the plate with an approximate ellipse shape and decreases from the edge of the tool shoulder to the outer side of the plate. Furthermore, the maximum temperature zone decreases gradually from tool shoulder to the bottom of the plate. In the welding zone, the equivalent strain is also distributed with ring shapes, and it decreases from the edge of the tool shoulder to the outer side of the plate.

Effect of Axial Pressure and Tool Rotation Speed on Temperature Distribution during Dissimilar Friction Stir Welding

2011 ◽  
Vol 418-420 ◽  
pp. 1934-1938 ◽  
Author(s):  
R. Padmanaban ◽  
V. Balusamy ◽  
V. Ratna Kishore
Keyword(s):  
Friction Stir Welding ◽  
Temperature Distribution ◽  
Rotation Speed ◽  
Maximum Temperature ◽  
Axial Pressure ◽  
Friction Stir ◽  
Tool Rotation Speed ◽  
Tool Shoulder ◽  
Dissimilar Aluminum Alloys ◽  
Tool Rotation

A computational fluid dynamics(CFD) based numerical model is developed to predict the temperature distribution during Friction Stir Welding(FSW) of dissimilar aluminum alloys. The effect of tool rotation speed and axial pressure on heat transfer during FSW has been studied. Numerical results indicate that the maximum temperature in FSW process can be increased with the increase of the axial pressure and tool rotation speed. The influence region of the tool shoulder in the direction of thickness can be increased with the increase in the axial pressure on the shoulder.

Finite Element Analysis and Simulation of Al 7075 Alloy Joints Produced by Friction Stir Welding

2015 ◽  
Vol 766-767 ◽  
pp. 1116-1120
Author(s):  
R. Ramesh ◽  
S. Suresh Kumar ◽  
V. Sivaraman ◽  
R. Mohan
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Axial Load ◽  
Maximum Temperature ◽  
Element Analysis ◽  
Friction Stir ◽  
Element Simulation ◽  
Al 7075 ◽  
7075 Alloy

The present work is mainly carried out to study the distribution of temperature in friction stir welded plate of Aluminium alloy. A 3-D finite element simulation model was developed to predict temperature distribution and residual stress in Friction Stir Welding (FSW) of Al 7075 alloy. The effect of angular velocity of tool, axial load and welding speed on the heat generated between the tool and plate to be welded was investigated. The simulations obtained were based on three factor five level central composite rotatable design. Second order polynomial equations for predicting the temperature was developed. Residual stresses for friction stir welded plates due to thermal cycles were predicted. The maximum temperature developed in friction stir welded plated increases with the increase of rotational speed of tool and axial load where as it decreases with increase in welding speed.

scholarly journals Influence of material velocity on heat generation during linear welding stage of friction stir welding

2016 ◽  
Vol 20 (5) ◽  
pp. 1693-1701
Author(s):  
Alin Murariu ◽  
Darko Veljic ◽  
Dragana Barjaktarevic ◽  
Marko Rakin ◽  
Nenad Radovic ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Friction Stir Welding ◽  
Heat Generation ◽  
Welding Process ◽  
Slip Rate ◽  
Frictional Heat ◽  
Al Alloy ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Pin

The heat generated during friction stir welding (FSW) process depends on plastic deformation of the material and friction between the tool and the material. In this work, heat generation is analysed with respect to the material velocity around the tool in Al alloy Al2024-T351 plate. The slip rate of the tool relative to the workpiece material is related to the frictional heat generated. The material velocity, on the other hand, is related to the heat generated by plastic deformation. During the welding process, the slippage is the most pronounced on the front part of the tool shoulder. Also, it is higher on the retreating side than on the advancing side. Slip rate in the zone around the tool pin has very low values, almost negligible. In this zone, the heat generation from friction is very low, because the material is in paste-like state and subjected to intensive plastic deformation. The material flow velocity around the pin is higher in the zone around the root of the pin. In the radial direction, this quantity increases from the pin to the periphery of the tool shoulder.

Friction stir welding of butt joints of 1420T1 and 1163T alloys sheets

2020 ◽  
pp. 446-453
Author(s):  
V.A. Berezina ◽  
V.V. Ovchinnikov ◽  
E.V. Luk’yanenko
Keyword(s):  
Friction Stir Welding ◽  
Ultimate Strength ◽  
Aluminium Alloys ◽  
Welded Joint ◽  
Butt Joint ◽  
Maximum Temperature ◽  
Butt Joints ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Rotation

The results of the butt joint formation of 5 mm thickness sheets from 1420T1 and 1163T aluminium alloys in different combination are presented. It is established that the ultimate strength of the joints depends on the location of the welded alloys relative to the direction of the tool rotation during friction stir welding. It is shown that depending on the location of 1420T1 and 1163T alloys on the side of the run in or out of the tool, the maximum temperature at the edge of the tool shoulder is 385 or 410 °C, in the weld core the metal is heated to 490 °C. The stir zone (the weld metal) consists of two zones corresponding to welded alloys without stir with each other. Ultimate strength to welded joint 1420T1 and 1163T alloys is 0.65...0.73 of ultimate strength to the 1420T1 alloy

Al Alloy Tailor welded Blanks Fabrication via Friction Stir Welding: Effect of Shoulder Size

2021 ◽  
pp. 1-9
Author(s):  
Tanveer Majeed ◽  
Nooruddin Ansari ◽  
Yashwant Mehta ◽  
Arshad Noor Siddiquee
Keyword(s):  
Friction Stir Welding ◽  
Butt Joint ◽  
Al Alloy ◽  
Second Phase ◽  
Thick Plates ◽  
Void Defect ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tailor Welded Blanks ◽  
Thermomechanical Behaviour

Abstract Material flow and heat generation by tool shoulder during Friction Stir Welding (FSW) significantly alters the microstructural and thermomechanical behaviour of joints. The effect of shoulder size on mechanical properties of joints has not yet been reported in the FSW of Tailor Welded Blanks (TWBs). This article reports the effect of shoulder size on joint quality in FSW of TWBs between 6.35 mm thick plates of AA2024-T3 and 2.5 mm thick plates of AA7475-T7 alloys in butt joint configuration fabricated under shoulder sizes: 18 mm, 20 mm, and 22 mm. Microstructural evaluation of FSWed joints reveals a significant increase in grain size with shoulder diameter sizes. The X-ray EDS elemental maps reveal the presence of fine second phase particles stir zone. The progressive elimination of void defect with the increase in shoulder size was observed. The tensile testing reveals the highest strength of joints fabricated under shoulder size of 18 mm. Fractographic analyses of broken tensile specimens showed the mixed mode of failure in all the weld specimens.

scholarly journals A coupled thermo-mechanical model of friction stir welding

2012 ◽  
Vol 16 (2) ◽  
pp. 527-534 ◽  
Author(s):  
Darko Veljic ◽  
Milenko Perovic ◽  
Aleksandar Sedmak ◽  
Marko Rakin ◽  
Miroslav Trifunovic ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Plastic Strain ◽  
Mechanical Model ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Bottom Surface ◽  
Al Alloy ◽  
Fe Model ◽  
Arbitrary Lagrangian Eulerian ◽  
Friction Stir

A coupled thermo-mechanical model was developed to study the temperature fields, the plunge force and the plastic deformations of Al alloy 2024-T351 under different rotating speed: 350, 400 and 450 rpm, during the friction stir welding (FSW) process. Three-dimensional FE model has been developed in ABAQUS/Explicit using the arbitrary Lagrangian-Eulerian formulation, the Johnson-Cook material law and the Coulomb?s Law of friction. Numerical results indicate that the maximum temperature in the FSW process is lower than the melting point of the welding material. The temperature filed is approximately symmetrical along the welding line. A lower plastic strain region can be found near the welding tool in the trailing side on the bottom surface. With increasing rotation speed, the low plastic strain region is reduced. When the rotational speed is increased, the plunge force can be reduced. Regions with high equivalent plastic strains are observed which correspond to the nugget and the flow arm.

scholarly journals Effect of High Rotational-Speed Friction-Stir Welding on Microstructure and Properties of Welded Joints of 6061-T6 Al Alloy Ultrathin Plate

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6012
Author(s):  
Hao Zhang ◽  
Shujin Chen ◽  
Yuye Zhang ◽  
Xinyi Chen ◽  
Zhipeng Li ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Rotational Speed ◽  
Heat Dissipation ◽  
Temperature Drop ◽  
Precipitation Amount ◽  
Large Angle ◽  
Welding Process ◽  
Al Alloy ◽  
High Rotational Speed ◽  
Friction Stir

The butt joint of an Al alloy ultrathin plate with a thickness of 0.5 mm is realized by a high rotational-speed friction-stir welding process. It overcomes the welding difficulty that the ultrathin plate is often torn, and it cannot be formed by conventional friction-stir welding. The results show that the weld surface is well-formed at a high-rotational speed (more than 8000 rpm), and there are no obvious defects in each area of the joint section. The nugget zone (NZ) is a recovery recrystallization structure dominated by large-angle grain boundaries, with a grain size of about 4.9 μm. During grain growth, the texture is randomly and uniformly distributed, and the strength is balanced. The microhardness of the NZ increases significantly with the increase in rotational speed, and the fluctuation range of hardness value is small. The NZ β–Mg2Si is finer and significantly less than the base metal (BM). The heat dissipation of the thin plate is fast, so a Cu plate is used as the backing plate to slow down the steep temperature-drop process in the weld area. Compared with a low rotational speed, the precipitation amount of brittle phase Al–Cu–Mg–Cr and Al–Fe–Si–Mn is significantly reduced, which is conducive to improving the mechanical properties of the joint. At a high rotational speed, 12,000 rpm, the best tensile strength of the joint is 220 MPa, which is about 76% of the BM (290 MPa), and the highest elongation is 9.3%, which is about 77.5% of the BM (12%). The fracture mode of the joint is a typical plastic fracture.

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